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                [Usaco2009 Feb]Surround the Islands 环岛篱笆                </h1>
                <p>时间限制：3s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
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                                <h3>题目描述</h3><p><div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;约翰在加勒比海买下地产，准备在这里的若干个岛屿上养奶牛．所以，他要给所有岛屿围上篱笆．每个岛屿都是多边形．他沿着岛屿的一条边界朝一个方向走，有时候坐船到另一个岛去．他可以从任意一个多边形顶点开始修篱笆的工作；在任意一个到达的顶点，他可以坐船去另一个岛屿的某个顶点，但修完那个岛的篱笆，他必须马上原路返回这个出发的岛屿顶点．任意两个顶点间都有肮线，每条航线都需要一定的费用．请帮约翰计算最少的费用，让他修完所有篱笆．</span></div></p><hr/><h3>输入格式</h3><p><div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;第1行输入N(3&le;N&le;500)，表示所有岛屿多边形的个数．</span></div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;接下来N行每行输入两个整数V1和V2(1&le;V1&le;N;1&le;V2&le;N)，表示一条构成岛屿的线段的两个端点．</span><span style="font-size: medium">接下来输入N行N列的矩阵，表示两个顶点间航行所需费用．</span></div></p><hr/><h3>输出格式</h3><p><div>&nbsp;</div>
<div><span style="font-size: medium">&nbsp;&nbsp;&nbsp;&nbsp;一个整数，最少费用．</span></div></p><hr/><h3>样例输入</h3><pre>12
1 7
7 3
3 6
6 10
10 1
2 12
2 9
8 9
8 12
11 5
5 4
11 4
0 15 9 20 25 8 10 13 17 8 8 7
15 0 12 12 10 10 8 15 15 8 8 9
9 12 0 25 20 18 16 14 13 7 12 12
20 12 25 0 8 13 14 15 15 10 10 10
25 10 20 8 0 16 20 18 17 18 9 11
8 10 18 13 16 0 10 9 11 10 8 12
10 8 16 14 20 10 0 18 20 6 16 15
13 15 14 15 18 9 18 0 5 12 12 13
17 15 13 15 17 11 20 5 0 22 8 10
8 8 7 10 18 10 6 12 22 0 11 12
8 8 12 10 9 8 16 12 8 11 0 9
7 9 12 10 11 12 15 13 10 12 9 0</pre><hr/><h3>样例输出</h3><pre>30</pre><hr/><h3>提示</h3><p><p><img height="472" width="817" alt="" src="../file/3397_0.jpg" /></p></p><hr/><h3>题目来源</h3><p>Silver</p>
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